This invention relates to a system for testing the electrical continuity and insulation of the electrical conductors of a portion of wiring. The term "portion of wiring" denotes a bunch of conductors--i.e., of electrical wires or cables--for transmitting the data and instructions necessary for the operation of a complex machine, inter alia an aircraft.
To check the electrical continuity and insulation of the conductors of a portion or length of wiring after its production at works and before it is fitted, for example, in an aircraft such as a helicopter, it is known to use a special test bench to which all the conductors of the wiring are connected.
It is known that such a system for testing the electrical continuity and insulation of the electrical conductors of a portion of wiring, each conductor having first and second connecting elements, comprises:
link means for linking with the first and second connecting elements of each conductor, the link means comprising a number of connecting elements to whose inputs the first and second connecting elements of each conductor can be connected; PA1 means for measuring an electrical parameter and connected to predetermined outputs of the connecting elements of the link means by way of means for selecting such outputs in order to connect the first and second connecting elements of the conductor under test to the measuring means so as to test the electrical continuity of such conductor, and in order to connect the conductor under test to at least some other conductors of the wiring in order to test the insulation of such conductor relatively to the other conductors; PA1 means for generating an electrical parameter identical to or different from the measured parameter, and PA1 means for piloting the system and analysing the tests.
In conventional test benches the means for selecting the outputs of the link connecting elements take the form of sets of selectors or switches and controls therefor. Consequently, for a test bench which may comprise several thousand test points, switches to the same number must be provided and even when ways and means for regrouping the switches are used the number of controls for the switches is still very high. Also, the need to be able to withstand voltage and the need for maintenance are two of several factors making it necessary to use specific switches known as reed switches. The same are embodied by two magnetic strips separated by an air gap and enclosed in a glass vessel in an inert atmosphere or in vacuo. To withstand the voltage the mass of magnetic material and the air gap between the reeds must be relatively large, and so a switch of this kind takes up appreciable space. The volume and weight of a conventional test bench are therefore considerable. For example, the size of a 8400-point test bench now currently used is approximately 4 m.sup.3 and it weighs from 600 to 700 kg, obviously with severe detriment to its mobility and flexibility of use. Also, the large number of controls (174 controls for an 8400 point test bench) means that the piloting means become very complex with a corresponding risk of breakdowns and poor reliability.